It’s a dangerous line of work, where they may be killed or forced to kill someone else. The former is tragic and the latter wreaks emotional havoc. As we know from news reports, post-traumatic stress disorder often leads to depression, domestic violence and sometimes suicide.

The dark and cloudy territory of mental trauma is not something the military — or anyone for that matter — deals with particularly well, and we often turn away from the problem, leaving veterans to wrestle their demons alone.

Is it right that we ask this of18-year-olds, knowing full well they don’t grasp the gravity of war? But we pull a mug of beer from their hands? Yank a credit card away?

To be clear, there is no movement I am aware of to raise the recruiting age to 21. It would be a nightmare for the American military, which relies heavily on teens with young bodies with pliable brains. Recruiting would surely take a nosedive if you gave every fresh-faced high school graduate a few more years to think about it.

But there seems to be collective confusion in American society about the age of adulthood.

We no longer expect 18-year-olds to act like adults, as we once did. After high school, most go to college or get a job, but they are by no means on their own.

If Junior is not still living at home, the parents are kicking in for rent or tuition while he or she spends a few years partying, traveling and soul searching before getting down to the business of being an adult, usually around the mid-20s. Sometimes later.